1. Field of the Invention
The present invention relates to a method and apparatus for separating petroleum which can efficiently separate a crude oil and refine gasoline or the like.
2. Description of the Related Art
There has been developed a method of distilling and refining a crude oil (see Japanese Unexamined Patent Publication (KOKAI) No. Hei 11-80754). In a method of separating a crude oil described in this publication, a crude oil is subjected to an atmospheric distillation and is thus separated into hydrocarbon mixtures having different components such as a residual oil, a light oil, kerosene, naphtha, an LP gas and a soft gas. In this method, the crude oil is heated to be a vapor, the vapor is liquefied and separated into hydrocarbon mixtures having different components to be refined.
A method of distilling and separating a crude oil requires a thermal energy in a large amount in order to vaporize the crude oil. The reason is that the vaporization heat of the crude oil is very high. Moreover, there is also employed a method of distilling or refining petroleum and separating the petroleum into a specific hydrocarbon mixture. Also in this method, a high thermal energy is required for vaporizing the petroleum into a vapor.
In a distilling process described in the aforementioned publication according to the prior art, a difference in a thermodynamic vapor pressure is utilized and a difference in a vaporization speed into a vapor phase at a certain pressure and temperature is thus used. This technique basically utilizes a vapor-liquid equilibrium relationship among large number of components. More specifically, a difference between the moving speeds of substances under a vapor saturation on the vapor phase side is utilized to obtain a driving force for a separation. As is easily imagined, however, the moving speed of the substance is increased when a difference in a vapor-liquid concentration is increased. From a viewpoint of a vapor-liquid equilibrium, the vapor phase side is filled with the vapor of a target substance. For this reason, originally, a speed at which the target substance can be moved from a liquid phase to the vapor phase is actually suppressed.
In the conventional distilling process, thus, the moving speed of a substance to be taken by an originally natural phenomenon is restricted. For this reason, a energy consumed by the whole apparatus is unnecessarily increased. In addition, the distilling process uses a boiler as a heat source. For such occasions, a very long time is required for warming up a whole huge distilling tower. In order to pursue economy, consequently, an operation is inevitably carried out for a long period of time to reduce the rate of occupation of a start-up time.
Moreover, the boiler is used as the heat source. For this reason, a nitride compound, a sulfur compound, a population substance of a floating granular substance and the like in a heavy oil to be a supplied substance are discharged in a large amount into the air after oxidation, and the discharge of carbon dioxide to be a warming substance becomes a social problem. Thus, the distilling technique for supporting a modern society has a large number of problems.
In order to atomize a solution, moreover, a method utilizing a spray nozzle or a centrifugal force is used in some cases. However, the method is not suitable for a separation process for the following reasons.    (1) A particle size is large;    (2) A higher energy than that in an ultrasonic atomizing method is required for obtaining an atomized fine particle having a small particle size;    (3) In a method of causing compressed air to collide with a liquid to be atomized, a temperature is dropped in an adiabatic expansion when the compressed air is released under an atmospheric pressure by using a compressor or the like. For this reason, a separation phenomenon utilizing an atmospheric heat cannot be expected in an atomizing portion.
The present invention has been developed in order to solve the drawbacks of the conventional methods. An important object of the present invention is to provide a method and apparatus for separating petroleum which can efficiently separate petroleum into hydrocarbon mixtures having different components by a small energy consumption.